Reflective liquid crystal display device

ABSTRACT

The present invention provides a method of manufacturing an active matrix reflecting liquid crystal display device including the step of forming and processing an interlayer insulating film. The step forming and processing an interlayer insulating film includes step A of forming the interlayer insulating film on a silicon film in which the sources and drains of TFTs are formed; step B of forming a photoresist layer on the interlayer insulating film; step C of patterning the photoresist layer in a specified pattern by using, as a photoresist mask for the photoresist layer, a mask having a pattern formed with a resolution limit or less corresponding to the reflecting electrode to be formed; and step D of etching the interlayer insulating film by using the photoresist layer patterned in step C as an etching mask. After step D, a metal film is deposited for simultaneously forming source electrodes, signal wiring, drain electrodes, and the reflecting electrode. The manufacturing method can thus be simplified to improve productivity.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a technique for simultaneously formingirregularity in a surface of a reflecting electrode and contact holes inan interlayer insulating film formed on a silicon film, in which sourcesand drains of TFTs are formed, above the sources or drains in a processfor manufacturing a reflective liquid crystal display device, to shortenthe manufacturing process.

2. Description of the Related Art

In a conventional active matrix reflective liquid crystal display devicein which each of pixel electrodes comprises a reflecting electrodeserving as a reflecting scattering plate by surface irregularity, adriving-side TFT substrate is manufactured as shown in FIG. 13. FIG. 13shows a manufacturing process for a liquid crystal device having a pixelstructure comprising bottom gate structure TFTs. However, a pixelstructure comprising top gate structure TFTs can also be manufactured bybasically the same process.

First, as shown in FIG. 13A, a metal film is deposited on a transparentsubstrate 1, and then dry-etched by photolithography to form gates G andauxiliary capacitance electrodes Cs. Then, a gate insulating film 2 isdeposited, and a polysilicon film 3 is further formed thereon.

Next, in order to prevent impurity injection into channel regions duringimpurity doping of source and drain regions, stoppers 4 are respectivelyformed on portions of the polysilicon film 3 corresponding to thechannel regions in self-alignment with the gates G, followed by impuritydoping of the source and drain regions.

Then, the polysilicon film 3 is separated into islands by photoresiststep and etching step to form low-temperature polysilicon thin filmtransistors (TFTs).

Next, an interlayer insulating film 5 is formed (FIG. 13B). In order toform contact holes in the interlayer insulating film 5, a photoresistlayer 6 is first formed on the interlayer insulating film 5, and thenpatterned by photolithography using a patterned mask as a photomask inwhich apertures are formed in portions corresponding to the contactholes (FIG. 13C). Then, the interlayer insulating film 5 is etched byusing the patterned photoresist layer 6 as an etching mask to formcontact holes H₁ in the interlayer insulating film 5 (FIG. 13D).

Next, a metal film is deposited by sputtering or the like, and thenetched to form source electrodes S₁ connected to sources S of the TFTsthrough the contact holes H₁, signal wiring, and drain electrodes D₁connected to drains D of the TFTs through the contact holes H₁ (FIG.13E).

Next, an irregular shape as a base for forming surface irregularity in areflecting electrode having a reflecting scattering ability is formed byusing two layers each comprising a photoresist material as follows.First, a first layer 7 for forming the basic structure of the irregularshape is formed by photolithography using a photoresist material (FIG.13F). The photomask used in this step has second contact holes H₂communicating with the source electrodes S₁ or the drain electrodes D₁.Next, a second layer 8 for improving the reflecting property is formedby photolithography using the same photoresist material as the firstlayer 7 (FIG. 13G). The photomask used in this step has third contactholes H₃ communicating with the drain electrodes D₁. In this way, thesurface irregular shape having a two-layer structure comprising thefirst and second layers 7 and 8 is formed.

Next, a metal film of Al, Ag, or the like, which has high reflectance,is deposited, and then subjected to photolithography to form areflecting electrode 10 (FIG. 13H).

In this way, the driving-side TFT substrate is completed. An alignmentfilm is coated on each of the TFT substrate and a counter substrate onwhich a color filter and a counter transparent electrode are formed, andthen subjected to alignment. Then, both substrates are bonded togetherwith a sealing material by using a gap material for keeping anappropriate gap between both substrates, and a liquid crystal isinjected into the gap, followed by sealing to obtain a liquid crystaldisplay panel.

The method of manufacturing a driving-side TFT substrate of aconventional active matrix reflective liquid crystal display deviceshown in FIG. 13 requires the steps of respectively forming the firstand second layers 7 and 8 each comprising a photoresist material andthen patterning the layers by photolithography to provide the reflectingelectrode 10 with the predetermined irregular surface shape. Therefore,a total of three insulating layers including the interlayer insulatingfilm 5 is finally formed between the silicon film, in which the sourcesS and drains D of TFTs are formed, and the reflecting electrode 10.Also, the method comprises the separate steps of forming the sourceelectrodes S₁ and the drain electrodes D₁, and forming the reflectingelectrode 10, to cause the problem of increasing the number of thesteps, thereby increasing the manufacturing cost.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to simplify theprocess for manufacturing an active matrix reflective liquid crystaldisplay device to improve productivity.

The inventors found a process for manufacturing a reflective liquidcrystal display device in which a photoresist layer was provided on aninterlayer insulating film formed on a silicon film in which sources anddrains of TFTs were formed, and then patterned by photolithography usinga specified photomask to simultaneously form apertures corresponding tocontact holes to be formed above the sources or the drains, and anirregular shape in the photoresist layer corresponding to the surfaceirregularity of a reflecting electrode, and then the interlayerinsulating film is etched by using the photoresist layer as an etchingmask to simultaneously the contact holes and the irregular surface shapein the interlayer insulating film corresponding to the reflectingelectrode. This could significantly shorten the process formanufacturing a liquid crystal display device.

Namely, the present invention provides a method of manufacturing anactive matrix reflective liquid crystal display device comprising aninterlayer insulating film formed on a silicon film in which sources anddrains of TFTs are formed, and a reflecting electrode having anirregular surface and formed on the interlayer insulating film, themethod comprising the step of forming and processing the interlayerinsulating film. The step of forming and processing the interlayerinsulating film comprises step A of forming the interlayer insulatingfilm on the silicon film in which the sources and drains of TFTs areformed, step B of forming a photoresist layer on the interlayerinsulating film, step C of patterning the photoresist layer byphotolithography, and step D of etching the interlayer insulating filmby using the photoresist layer patterned in step C as an etching mask.Step C uses, as a photoresist mask for the photoresist layer, a maskhaving a pattern formed with a resolution limit or less in a portioncorresponding to the reflecting electrode to be formed, so that portionsof the photoresist layer corresponding to the contact holes to be formedin the interlayer insulating film above the sources or drains can becompletely removed, and surface irregularity can be formed in a portionof the photoresist layer corresponding to the reflecting electrode to beformed. In step D, portions of the interlayer insulating filmcorresponding to the contact holes are completely opened, and surfaceirregularity is formed in a portion of the interlayer insulating filmcorresponding to the reflecting electrode to be formed.

The manufacturing method further comprises, after step D, step E ofdepositing a metal film for simultaneously forming source electrodescommunicating with the sources through the contact holes, signal wiring,drain electrodes communicating with the drains through the contactholes, and the reflecting electrode, step F of depositing a protectingfilm and patterning the protecting film to open portions of theprotecting film corresponding to contact holes to be formed above thedrain electrodes, and step G of forming a transparent conductive film onthe protecting film so that the transparent conductive film is connectedto the reflecting electrode through the contact holes. In step F offorming the protecting film comprising photoresist and patterning theprotecting film, a mask having a pattern formed with a resolution limitor less in a portion corresponding to the reflecting electrode to beformed is used as a photoresist mask for the protecting film so thatportions of the protecting film corresponding to the contact holes to beformed above the drains can be completely removed, and surfaceirregularity can be formed in the portion of the protecting filmcorresponding to the reflecting electrode to be formed.

The manufacturing method may further comprise, after step D, step E ofdepositing a metal film for simultaneously forming source electrodescommunicating with the sources through the contact holes, signal wiring,drain electrodes communicating with the drains through the contactholes, and the reflecting electrode, and step G_(y) of forming atransparent conductive film on the reflecting electrode so that thetransparent conductive film is connected to the reflecting electrode.

The manufacturing method may further comprise, after step D, step E_(x)of depositing a transparent conductive film for simultaneously formingpattern portions corresponding to source electrodes communicating withthe sources through the contact holes, signal wiring, drain electrodescommunicating with the drains through the contact holes, and thereflecting electrode, and step G_(y) of forming a transparent conductivefilm on the reflecting electrode so that the transparent conductive filmis connected to the reflecting electrode.

The present invention also provides an active matrix reflective liquidcrystal display device comprising an insulating layer formed on asilicon film in which sources and drains of TFTs are formed, and areflecting electrode having an irregular surface and formed on theinsulating layer, wherein the insulating layer comprises a singleinsulating film.

The liquid crystal display device further comprises a transparentconductive film formed on the reflecting electrode so that thetransparent conductive film is connected to the reflecting electrode,and a protecting film provided between the reflecting electrode and thetransparent conductive film so that the cell gap of a liquid crystaldisplay cell is set to ¼λ, wherein surface irregularity is formed in thetransparent conductive film formed on the reflecting electrode.

In the liquid crystal display device of the present invention, thereflecting electrode may be deposited on the insulating layer throughthe transparent conductive film.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a drawing illustrating the steps of a method of manufacturinga liquid crystal display device according an embodiment of the presentinvention;

FIG. 2 is a sectional view of a TFT substrate obtained by amanufacturing method of the present invention;

FIG. 3 is a drawing illustrating the steps of a method of manufacturinga liquid crystal display device of the present invention;

FIG. 4 is a sectional view of a TFT substrate obtained by amanufacturing method according to another embodiment of the presentinvention;

FIG. 5 is a sectional view of a TFT substrate obtained by amanufacturing method according to a further embodiment of the presentinvention;

FIG. 6 is a plan view of a photomask having a L/S pattern;

FIG. 7 is a graph showing the relation between L/S of a photomask, theexposure time and the thickness decrement of a photoresist layer in thephotolithography step for a photoresist layer;

FIG. 8 is a plan view of a photomask having a dot pattern;

FIG. 9 is a plan view of a photomask used for a photoresist layer;

FIG. 10A is a plan view of the pattern of a photomask for formingsurface irregularity in a photoresist layer, and FIG. 10B is a side viewof the surface irregularity of the photoresist layer formed by using themask;

FIG. 12 is a graph showing the relation between the step of surfaceirregularity of a reflecting electrode and reflectance; and

FIG. 13 is a drawing illustrating a conventional process formanufacturing an active matrix reflective liquid crystal display device.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will be described in detail below with referenceto the drawings. In the drawings, the same reference numeralsrespectively denote the same or equivalent components.

FIG. 1 is a drawing illustrating the steps of a method of manufacturinga liquid crystal display device having a pixel structure comprisingbottom gate structure TFTs according to an embodiment of the presentinvention.

In this method, as shown in FIG. 1A, a metal film of Mo, Cr, Al, Ta, W,or the like is first deposited on a transparent substrate 1, and thendry-etched by photolithography to form gates G and auxiliary capacitanceelectrodes Cs, and a silicon nitride film or silicon oxide film, or alaminate thereof is formed as a gate insulating film 2 by sputtering orCVD. Furthermore, a polysilicon film 3 is formed on the gate insulatingfilm 2. The polysilicon film forming method comprises forming asemiconductor layer on the gate insulating film 2, dehydrogenating thesemiconductor layer by high-temperature treatment in order to decreasethe hydrogen concentration of the semiconductor layer, and thencrystallizing the semiconductor layer with an excimer laser to convertthe semiconductor layer to the polysilicon film. With a hydrogenconcentration of 1 atomic % or less, the dehydrogenating step may beomitted. In order to stabilize film quality, the gate insulating filmand the semiconductor layer are preferably continuously deposited.

Next, in order to prevent impurity injection into channel regions duringimpurity doping of source regions and drain regions, stoppers 4 arerespectively formed on the portions of the polysilicon film 3, in whichthe channel regions are formed, in self-alignment with the gates G. Thestoppers 4 are formed by depositing a stopper film comprising siliconoxide on the gate insulating film 2, coating a resist on the stopperfilm, exposing the resist layer from the back side using the gates G asa mask to pattern the resist corresponding to the channel regions inself-alignment with the gates G, and then etching the stopper film byusing the resist as a mask to leave the stopper film in the portionscorresponding to the channel regions.

Then, the source regions and drain regions are doped with impurities byan ion implantation or ion doping method to form sources S and drains D.The polysilicon film is divided into islands by using a photoresist stepand an etching step to form TFTs. The above-described method of formingTFTs is a method of forming low-temperature polysilicon thin filmtransistors, and the manufacturing method of the present invention canalso be applied to the formation of amorphous silicon thin filmtransistors.

The next step of forming and processing an interlayer insulating filmcomprises the following steps A to D.

Step A: The interlayer insulating film 5 comprising an inorganicinsulating material such as a silicon nitride film a silicon oxide film,a laminate of these films, or the like is formed by the CVD orsputtering process (FIG. 1B).

Step B: A photoresist layer 6 is formed on the interlayer insulatingfilm 5.

Step C: The photoresist layer 6 is patterned by photolithography (FIG.1C). In this step, a mask having a pattern formed with a stepperresolution limit or less corresponding to the reflecting electrode to beformed is used as a photomask for the photoresist layer 6 so thatportions of the photoresist layer 6 corresponding to the contact holesH₁ to be formed in the interlayer insulating film 5 above the sources Sor the drains D are completely removed, and surface irregularity isformed in a portion of the photoresist layer 6 corresponding to thereflecting electrode to be formed.

The shape of the photomask can be determined by experimentallydetermining the relation between the pattern of the photomask, thethickness decrement of the photoresist layer and the exposure time. Forexample, when the line/space (referred to as “L/S” hereinafter) patternshown in FIG. 6 is exposed through the stepper, the relation between thethickness decrement of the photoresist layer and the exposure timechanges according to L/S, as shown in FIG. 7. In FIG. 7, “Window”represents a case in which S is higher than the resolution of anexposure device, and the numerical values on the right side of symbolsx, etc. denote L (μm)/S (μm). FIG. 7 indicates that with an exposure of1200 msec with which portions of the photoresist layer corresponding tothe contact holes to be formed are completely opened, the thicknessdecrement of the photoresist layer can be set to 0.6 μm when L=0.25 μmand S=0.50 μm.

In experimentally determining the thickness decrement of the photoresistlayer, the dot patter shown in FIG. 8 may be used in place of the L/Spattern shown in FIG. 6.

Besides these methods, the more definite shape of the photomask can becalculated from the constants of an optical system, and thus thethickness of the photoresist layer can be controlled by the effectivetransmittance of the photomask.

As the actual pattern of the photomask, a pattern which can be resolvedby the stepper is provided stepwise or continuously. For example, informing a portion 21 where the photoresist layer is completely opened byexposure, and a portion where surface irregularity is formed in thephotoresist layer, each of the pattern portions 22 shown in FIG. 22where surface irregularity is formed can be formed in a cyclic patterncomprising a plurality of fine concentric circles which cannot beresolved by the stepper. By exposure and development using such aphotomask for the photoresist layer, the completely open portion and theportion where surface irregularity is formed can be formed in thephotoresist layer. However, by heating reflow after development, theshape of each of the pattern portions of the photoresist layer 6 inwhich surface irregularity is formed, can be smoothed, as shown in FIG.10B.

As the pattern of the photomask, a specified pattern may be used, whichcorresponds to the shape of surface irregularity so as to form surfaceirregularity in the interlayer insulating film 5 to increase thereflectance of the reflecting electrode in the specified direction. Forexample, as shown in FIG. 11A, a plurality of circular patterns aredecentered. By exposure and development, and, if required, reflow usingthis photomask for the photoresist layer 6, the pattern portions of thephotoresist layer 6, in which surface irregularity is formed, can beformed in a shape in which one of the sides steeply slopes, and theother side gently slopes.

Also, the reflectance of the reflecting electrode depends upon the stepdifference of the pattern formed in the photoresist layer 6, as shown inFIG. 12, and the step difference of the pattern depends upon the patternshape of the photomask, the exposure, etc. Therefore, the pattern of thephotomask, and the exposure of the photoresist layer 6 are appropriatelyset so as to form a step difference which permits the reflectingelectrode to obtain predetermined reflectance.

Then, the interlayer insulating film 5 is dry-etched by using thepatterned photoresist layer 6 as the etching mask to transfer the shapeof the photoresist layer 6 to the interlayer insulating film 5.Therefore, the following step D is performed.

Step D: The interlayer insulating film 5 is etched by a resist back-stepdry etching method such as a RIE or ICP method, or the like using thephotoresist layer 6 patterned in the above-described step C as theetching mask so that the portions of the interlayer insulating film 5corresponding to the contact holes H₁ to be formed are completelyopened, and surface irregularity is formed in the portion of theinterlayer insulating film 5 corresponding to the reflecting electrodeto be formed (FIG. 1D).

After the interlayer insulating film 5 is formed in step D, aninsulating film need not be further deposited for forming surfaceirregularity in the reflecting electrode. Therefore, a metal film isdeposited on the interlayer insulating film 5 to form the reflectingelectrode, thereby simply obtaining the driving-side TFT substrate andmanufacturing an active matrix reflective liquid crystal display device.In this case, any desired method can be used for forming the reflectingelectrode, and any layers such as a protecting layer, and the like maybe further provided according to demand. By using the TFT substrate, aliquid crystal display panel can be produced by a conventional method tomanufacture a liquid crystal display device.

The thus-produced liquid crystal display device is the same as a knownactive matrix reflective liquid crystal display device in that theinsulating layer is formed on the silicon film in which the sources Sand the drains D of the TFTs are formed, and the reflecting electrodehaving surface irregularity and serving as a reflecting scattering plateare formed on the insulating layer. However, the liquid crystal displaydevice of the present invention is characterized in that the insulatinglayer between the silicon film and the reflecting electrode comprises asingle insulating film. Therefore, the present invention includes aliquid crystal display device having such a structure.

The method of manufacturing a liquid crystal display device of thepresent invention further comprises the following steps E to G, whichare successively performed after step D, as shown in FIGS. 1E to 1G.

Step E: A metal having a high reflectance, such as Al, Ag, an Al alloy,an Ag alloy, or the like, is deposited by sputtering to form a metalfilm 11, patterned by photolithography and then etched to simultaneouslyform the source electrodes S₁ communicating with the sources S throughthe contact holes H₁, signal wiring, the drain electrodes D₁communicating with the drains D through the contact holes H₁, and thereflecting electrode (FIG. 1E). In this case, the metal film 11 may havea multilayer structure comprising a conductive film of Al, Ag, an Alalloy, or an Ag alloy having high reflectance, and a metal film of Cr,Mo, Ti, Ta, W, or the like.

Step F: A protecting film 12 comprising photoresist is formed in aregion including the reflecting electrode 10, and then patterned to formholes at positions of the protecting film 12, which correspond to thedrain electrodes D₁ (FIG. 1F). As the method of forming the protectingfilm 12, a silicon oxide or the like may be deposited and then patternedby photolithography and etching. However, from the viewpoint ofshortening the process, the preferred method comprises depositing aphotoresist and then patterning the deposited film only byphotolithography, like the above-described step F.

The thickness of the protecting film 12 is preferably set so that thecell gap of a liquid crystal cell is ¼λ. This cell gap of the liquidcrystal cell is generally required from the viewpoint of brightening thescreen of the reflective liquid crystal display panel.

The protecting film 12 is not necessarily formed in the region includingthe reflecting electrode 10, and the protecting film 12 may be formedonly in the region excluding the pixel region to form the TFT substrate,as shown in FIG. 2.

Step G: As shown in FIG. 1G, a transparent conductive film 9 is formedon the protecting film 12 to be patterned to cover the reflectingelectrode to obtain the TFT substrate. The transparent conductive film 9is deposited by, for example, sputtering ITO, and then patterning thedeposited film by photolithography and etching. In the presentinvention, the transparent conductive film 9 is not necessarily providedon the reflecting electrode 10. However, the transparent conductive filmis electrically connected to the reflecting electrode 10 at the samepotential through the contact holes H₂ to prevent a precipitationphenomenon in which Ag of the reflecting electrode 10 is transferred tothe counter substrate in the liquid crystal cell.

The liquid crystal cell is obtained by coating an alignment film on eachof the TFT substrate obtained as described above, and the countersubstrate on which a color filter and a counter electrode are formed,performing alignment, bonding both substrate together with a sealingmaterial to maintain an appropriate gap between both substrates,injecting a liquid crystal, and then sealing the substrates.

In a manufacturing method according to another embodiment of the presentinvention, the above-described step F of patterning the protecting film12 is performed by exposing and developing the protecting layer 12using, as a photomask for the protecting film 12, a mask having apattern formed with a resolution limit of the stepper or lesscorresponding to the reflecting electrode to be formed, so that theportions of the protecting film 12 comprising photoresist, whichcorrespond to the contact holes to be formed above the drain electrodesD₁, can be completely removed, and surface irregularity can be formed inthe portion which corresponds to the reflecting electrode to be formed,according to the above step C of patterning the photoresist layer 6. Bythis method, the protecting film 12 can be patterned, as shown in FIG.3A.

After the protecting film 12 is patterned, like in the above-describedstep G, the transparent conductive film 9 is formed on the protectingfilm 12 to obtain the TFT substrate. In the thus-obtained TFT substrate,external light incident on the nearly plane-reflecting bottom of thesurface irregularity of the reflecting electrode 10 is scattered due toa difference between the refractive indexes of the protecting film 12and the transparent conductive film 9 to decrease the ratio of externallight incident on the flat portion of the reflecting electrode 10, andthe light reflected by the reflecting electrode 10 is further scatteredto improve the reflection performance of pixels.

A manufacturing method according to a further embodiment of the presentinvention comprises forming the transparent conductive film 9 in thesame manner as step G without forming the protecting film on the pixelregion after the source electrodes S₁, signal wiring, the drainelectrodes D₁ and the reflecting electrode 10 is formed in theabove-described step E to produce such a TFT substrate as shown in FIG.4.

Alternatively, after the step D of etching the interlayer insulatingfilm 5, the following steps E_(x) and G_(x) may be successivelyperformed to produce a TFT substrate in which the reflecting electrode10 is deposited on the transparent conductive film 9, as shown in FIG.5.

Step E_(x): The transparent conductive film 9 is deposited to form apattern including the portions which correspond to the source electrodesS₁ communicating with the sources S through the contact holes H₁, signalwiring, the drain electrodes D₁ communicating with the drains D throughthe contact holes H₁, and the reflecting electrode 10.

Step G_(x): A metal film of Al, Ag, an Al alloy, an Ag alloy, or thelike is deposited to form the reflecting electrode 10 so that thereflecting electrode 10 is connected to the transparent conductive film9.

When ITO is deposited for forming the transparent conductive film 9, Moor Ti is preferably deposited on the ITO film, and then the metal film11 is deposited thereon.

Although the present invention has been described above with referenceto the drawings, various other embodiments can be made. For example,although the drawings show a liquid crystal display device having apixel structure comprising bottom-gate structure TFTs, the presentinvention can be applied to a liquid crystal display device having apixel structure comprising top-gate structure TFTs.

In accordance with the present invention, a method of manufacturing anactive matrix reflective liquid crystal display device comprisesproviding a photoresist layer on an interlayer insulating film formed ona silicon film in which sources and drains of TFTs are formed,patterning the photoresist by using a specified photomask tosimultaneously form apertures corresponding to contact holes to beformed above the sources or drains and a shape corresponding to surfaceirregularity of a reflecting electrode, and etching the interlayerinsulating film by using the photoresist layer as an etching mask tosimultaneously form the contact holes in the interlayer insulating filmand the surface irregularity shape of the reflecting electrode. It isthus possible to reduce the steps of laminating a photoresist layerrequired for forming a surface irregularity shape of a reflectingelectrode in a conventional active matrix reflecting liquid crystaldisplay device. Also, source electrodes, signal wiring, drain electrodesand reflecting electrodes, which are formed in separate steps in aconventional method, can be simultaneously formed by depositing a singlemetal film and patterning it. Therefore, the process for manufacturing aliquid crystal display device can be significantly simplified to improveproductivity.

In the present invention, a transparent conductive film may be formed onthe reflecting electrode so that the transparent conductive film iselectrically connected to the reflecting electrode at the samepotential, thereby preventing a precipitation phenomenon in which Ag ofthe reflecting electrode is transferred to a counter substrate in aliquid crystal display cell.

Furthermore, in the present invention, a protecting film may be providedbetween the reflecting electrode and the transparent conductive film sothat the optical properties of the liquid crystal display cell caneasily be optimized by controlling the thickness of the protecting film.

1-8. (canceled)
 9. An active matrix reflective liquid crystal displaydevice comprising an insulating film formed on a silicon film in whichsources and drains of TFTs are formed, and a reflecting electrode havingan irregular surface and formed on the insulating film, wherein theinsulating layer comprises a single insulating film.
 10. A liquidcrystal display device according to claim 9, further comprising atransparent conductive film formed on the reflecting electrode so thatthe transparent conductive film is connected to the reflectingelectrode.
 11. A liquid crystal display device according to claim 10,further comprising a protecting film provided between the reflectingelectrode and the transparent conductive film so that the cell gap of aliquid crystal display cell is set to ¼λ.
 12. A liquid crystal displaydevice according to claim 11, wherein the surface irregularity is formedin the transparent conductive film formed on the reflecting electrode.13. A liquid crystal display device according to claim 9, wherein thereflecting electrode is deposited on the insulating layer through thetransparent conductive film.